Various liquid supply assemblies have been described for use with gravity fed liquid (e.g., paint) spraying devices or spray guns, including those described in the international application published as International Publication Number WO 98/32539 on Jul. 30, 1998, the content whereof is incorporated herein by reference. The supply assembly including a collapsible liner that is described and claimed in that application should provide advantages over the prior art liquid supply assembly also described in that application.